Artificial leg



ANLPHOTO-LITHO. CD. NN, (OSBURNES PRBCESS.)

UNITED STATES PATENT OFFICE.

B. F'. PALMER, OF PHILADELPHIA, PENNSYLVANIA.

ARTIFICIAL LEG.

Specification of Letters Patent No. 9,200, dated August 17, 1852.

To all whom 'it may concern:

Be it known that I, B. FRANK PALMER, of the city and county of Philadelphia and St-ate of Pennsylvania, have invented certain new and use-ful Improvements in Artificial Legs; and I do hereby declare that the following is a full and exact description thereof, reference being had to the accompanying drawings, making part of this specification, in which- Figure 1, is a vertical section of my improved artificial leg when straight; Fig. 2, a like view of the same when flexed; Fig. 3, view of a part detached, and Figs. 4 and 5, views of parts detached, and exhibiting certain modicat-ions of arrangement in said parts.

Like parts are designated by like letters in all the figures.

There have hitherto been but two modes of inserting the tendo Achillis (or heel cord,) in artificial legs applying above the knee. One of these modes consists in attaching the tendo Achillis tothe heel of the foot and passing it direct-ly to some portion of the thigh, as in the Anglesey leg and others. The other mode consists in fastening the upper end of the tendo Achillis immov ably to some portion ofthe leg below the knee.

The first described manner is objectionable inasmuch as, at every step, when the weight of the person is borne upon the ball of the foot, the tendo Achillis has a powerful tendency to flex the knee and thus render the step insecure. The diiiiculty attending this arrangement has never been obviated without producing other equally objectionable results, and a departure from correct anatomical principles, either in the position of the entire limb or of its articulations.

The second mode, as by myself introduced in my patent bearing date, November 4, 1846, gives stability to the knee, but does not allow sufficient motion of the ankle to enable a person, having a very short stump, to raise the anterior portion of the foot so as to clear obstructions and irregularities of the ground with so great facility as desirable. To give all desirable upward motion to the front portion of the foot, and to insure entire stability of the knee I have inserted the following described mechanism.

The nature of my invention consists, first, in making the upper attachment of the tendo Achillis movable during the act of bending or extending the leg, and nearly or quite immovable, at the moment when the leg is extended, by means of a vibrating lever w, and an auxiliary tendon s, reaching from said lever, in the lower leg, up to a convenient position in the thigh; by the peculiar construction and operation of which mechanism, substantially as hereinafter set forth, any desired extent of upward motion may be given to the anterior portion of the foot, and the tendency to bend the extended leg or throw the thigh forward by the tension of the tendo Achillis, when the weight kof the body is thrown upon the ball of the foot in walking, is nearly or entirely obviated ;-and secondly, in the improved combination and arrangement of an elastic cord 70, and vibratory brace a, for raising the front part of the foot and for producing the proper movements of the toe-piece.

The general construction o-f my improved artificial leg is the same as described by me in the specifications of Letters Patents of the United States, granted to me, and bearing dates of November fourth 1846, and February twentieth 1849. But instead of attaching the tendo Achillis as therein described, I now make use of the following additional device, with which said tendon is connected, and by which the desired results are secured, viz The lower end of said tendo Achillis t, is attached to the heel in any convenient manner and position. Its upper end is attached to a lever fw, which is situated in a suitable position within the lower leg B, and vibrates in a perpendicular plane upon a proper fulcrum at one end. I usually employ, for a fulcrum, a boltc, having its bearings in the shell of the leg. Said bolt may be fixed in its bearings, by cutting its ends obliquely and parallel with the outer curvature of the shell, to which it should not quite reach, but leave room to insert a little plate over each end and thereby hold it immovably in its place. When the bolt is thus inserted the lever should vibrate freely on it. Instead of making the bolt immovable in its bearings, I sometimes cause it to vibrate therein, and attach firmly to it the lever. A convenient manner of attaching said lever to its bolt is to make the bolt square in that portion along which the lever is to be joined to it, and round in the remainder of its extent; then cut a dove-tail` notch in one side of the square portion of the bolt, into which the end of the lever, made of a corresponding shape, is inserted. The whole is secured by passing a pin through the centers of both lever and bolt. I usually make the tendo Achillis of a double cord united at the top, or otherwise form its upper end into a loop. I then pass said loop around the lever fw, and insert it into a notch cut, to receive it, in the upperV side of the lever, a proper distance (say inch) from its fulcrum. The tendon should sink into the notch just far enough to fall below the surface of the lever, and it is held therein by a small strip of leather f, passing over, and inclosing, the mouth of the notch.

G lose to the lever on both sides, the bolt e, is notched, as at Z), sufliciently deep to receive the cent-er of the tendo Achillis nearly, but never quite, into its own center, when the lever is'raised to its highest position over its fulcrum. By this means the tension of said tendon will be in a direction nearly through the center of the bolt. A second tendon s, is attached to the under side of the end of the lever fw, opposite to its fulcrum, and passes around the end of the lever up to a proper position in the rear of the thigh A, where its upper end is attached. A small arm 7", is secured to the shell of the leg just below the lever fw, and serves to prevent the lever descending too far. lVhen the leg is bent, the tendon s, becomes slackened, thereby allowing the lever w, to descend to the stop r. The tendo Achillis descends with said lever, and thereby allows the anterior portion of the foot to be raised by the elastic tendon m, as far as desirable. When the leg is extended, the tendon s, is straightened and drawn upward sufliciently far to raise the lever fw, over its fulcrum till the point of attachment of the tendo Achillis to said lever is raised to that position, in which the tension of said tendon will be nearly poised over the fulcrum of the lever, and consequently have almost no power to draw down the lever.

In Figs. 4 and 5, are seen modifications of the arrangement of the lever and tendons. In Fig.A 4, the center line of the tendon z5, passes precisely through the center of the bolt e; and in Fig. 5, t-he said center line is carried even a littlebeyond the center of the bolt, when t-he lever is brought to its highest position. In both these cases I make use of a spring or elastic cushion z', against which the lever w, presses slightly aject'ed to the liability of a misstep from an untimely bending of the knee. Secondly, instead of the coiled spring and cords, giving action t-o the ankle and toes, as described in my'patent bearing date of February 20, 1849, I now employ the following arrangement: To the under portion of the toe-piece I attach, in any convenient man-VV ner, the cord m. I also secure to the arch of the instep -a vibratory brace p, by means of a small strip of leather a, forming a kind of hinge. Said brace extends obliquely downward and backward in the foot sufficiently vfar to accomplish the purpose intended-by :its use.

The said cord m, extends backward from the toe-piece in a nearly horizontal di- Irection, and, being securely attached to the 'lower end of the aforesaid brace, is then passed upward in the hollow of the lower leg B, and fastened, in any convenient manner, to some portion of its shell. may be itself an elastic substance, such as 'vulcanized gutta-peroha or india-rubber, or

Said cord a superior qualityfof cat-gut. But an in- .elastic cord may be'used by attaching its -upper end to any suitable spring n. The

oflice of the vibrating brace is to keep the cord m, in a proper position for performing its functions. The elastic cord serves as a spring to raise the anterior portion of the foot, and also to depress the toes at the proper time.

AI am aware that the tendo Achillis has been extended upward and attached to the thigh piece, for the purpose of drawing upward the heel and depressing the forward ypart of the foot, when the leg is st-raightened, and-therefore I do not claim that arrangement as my invention; but

What I do claim as new and desire to secure by Letters Patent, is-

l. Attaching the upper end of the tendo Achillis to a leveror to its equivalent mover-which is united to an auxiliary tendon, that descends from its connection with the thigh piece; and also, the so arranging of the said lever and tendons, that when the weight ofthe person is thrown upon the ball of the foot, in'walking, the powerful downward strain, which will thereby be exerted upon the tendo Achillis, will exert little or no influence upon the said auxiliary tendon; (which descends from the thigh-piecegk or, at any rate, no influence that will have an appreciable tendency to bend the knee, or The above specification of my improvegive instability thereto, substantially as ments in artificial legs signed this 16th day herein set forth. of April 1852.

2. I also claim the vibratory brace p, and B. FRANK PALMER. 5 elastic cord m, operating in combination= Witnesses:

substantially in the manner and for the pur- Z. C. ROBBINS,

poses herein set forth. J. S. BROWN. 

